jim hamblen / Mbed 2 deprecated flash_audio_player_8bit

Plays audio samples from an array stored in flash. Values are from an audio *.wav file that was automatically converted to a C array data source file. 8-bit samples used in this version.

Dependencies:   mbed

Fork of flash_audio_player by jim hamblen

See https://os.mbed.com/users/4180_1/notebook/using-flash-to-play-audio-clips/ for details on setup

main.cpp@1:bd7bef7df00b, 2017-10-22 (annotated)

Committer:
4180_1
Date:
Sun Oct 22 16:12:03 2017 +0000
Revision:
1:bd7bef7df00b
Parent:
0:e4f991474a45 
ver 1.0

Who changed what in which revision?

UserRevisionLine numberNew contents of line
4180_1 0:e4f991474a45 1 #include "mbed.h"
4180_1 0:e4f991474a45 2 AnalogOut speaker(p18);
4180_1 0:e4f991474a45 3 Ticker sampletick;
4180_1 0:e4f991474a45 4 DigitalOut myled(LED1);
4180_1 0:e4f991474a45 5 //Plays Audio Clip using Array in Flash
4180_1 1:bd7bef7df00b 6 //8-bit audio samples used
4180_1 0:e4f991474a45 7 //setup const array in flash with audio values
4180_1 0:e4f991474a45 8 //from free wav file conversion tool at
4180_1 0:e4f991474a45 9 //http://ccgi.cjseymour.plus.com/wavtocode/wavtocode.htm
4180_1 0:e4f991474a45 10 //see https://os.mbed.com/users/4180_1/notebook/using-flash-to-play-audio-clips/
4180_1 1:bd7bef7df00b 11 #include "cylon8bit.h"
4180_1 0:e4f991474a45 12
4180_1 0:e4f991474a45 13 #define sample_freq 11025.0
4180_1 0:e4f991474a45 14 //get and set the frequency from wav conversion tool GUI
4180_1 0:e4f991474a45 15 int i=0;
4180_1 0:e4f991474a45 16
4180_1 1:bd7bef7df00b 17 union short_or_char {
4180_1 1:bd7bef7df00b 18 short s;
4180_1 1:bd7bef7df00b 19 char c[2];
4180_1 1:bd7bef7df00b 20 };
4180_1 1:bd7bef7df00b 21
4180_1 1:bd7bef7df00b 22 union short_or_char sample;
4180_1 1:bd7bef7df00b 23
4180_1 1:bd7bef7df00b 24
4180_1 0:e4f991474a45 25 //interrupt routine to play next audio sample from array in flash
4180_1 0:e4f991474a45 26 void audio_sample ()
4180_1 0:e4f991474a45 27 {
4180_1 1:bd7bef7df00b 28 sample.c[1] = sound_data[i];
4180_1 1:bd7bef7df00b 29 speaker.write_u16(sample.s);
4180_1 0:e4f991474a45 30 i++;
4180_1 0:e4f991474a45 31 if (i>= NUM_ELEMENTS) {
4180_1 0:e4f991474a45 32 i = 0;
4180_1 0:e4f991474a45 33 sampletick.detach();
4180_1 0:e4f991474a45 34 myled = 0;
4180_1 0:e4f991474a45 35 }
4180_1 0:e4f991474a45 36 }
4180_1 0:e4f991474a45 37 int main()
4180_1 0:e4f991474a45 38 {
4180_1 1:bd7bef7df00b 39 sample.c[0] = 0; //setup fast byte to short conversion using union
4180_1 0:e4f991474a45 40 while(1) {
4180_1 0:e4f991474a45 41 myled = 1;
4180_1 0:e4f991474a45 42 //use a ticker to play send next audio sample value to D/A
4180_1 0:e4f991474a45 43 sampletick.attach(&audio_sample, 1.0 / sample_freq);
4180_1 0:e4f991474a45 44 //can do other things while audio plays with timer interrupts
4180_1 0:e4f991474a45 45 wait(10.0);
4180_1 0:e4f991474a45 46 }
4180_1 0:e4f991474a45 47 }